Question

A segment of a roadway has a free flow speed of 45 mph and a jam density of 25 ft per vehicle. Determine the maximum flow and at a flow rate of 1950 vph

Answer 1

Answer:

2376 vph

Explanation:

Given data

free flow speed ( Vf ) = 45 mph

Jam density = 25 ft per vehicle

flow rate = 1950 vph

first we calculate the Jam density in vehicle /mile

= 5280 / 25 = 211.2 vehicle/mile

where ; 1 mile = 5280 feet

The maximum flow can be calculated using Greenshield method

q = ( Vf * jam density ) / 4  =  ( 45 * 211.2 ) / 4

  = 2376 vph